1. Field
The present disclosure generally relates to systems and methods for correcting spinal deformities.
2. Description of the Related Art
The treatment of spinal deformity requires a three dimensional approach and therefore is organized into three primary planes of correction relative to the human body. These three planes include the frontal or coronal plane, the sagittal or lateral plane, and the transverse or axial plane as shown in FIG. 1. Correction and proper alignment of these three planes is often the goal of the surgeon in the treatment of spinal deformity. Spinal deformities of varying etiologies are well known.
Over the past several decades, spinal fusion has been chosen as the standard of practice in the treatment of spinal deformity. Spinal fusion is the implantation of a rigid construct that may include rods, bone screws, hooks, and wires.
Early treatment of spinal deformity, more specifically scoliosis, involved a Harrington Rod developed by Dr. Paul Harrington. During this particular procedure, the Harrington rod is implanted along the spinal column to treat, among other conditions, a lateral or coronal plane curvature of the spine. With this procedure, no special attention was made to treat the sagittal or axial planes of alignment and as a result “Flatback Syndrome” developed whereby the spine progressively grew into an unnatural, straightened position with limited lordosis.
Years later, Dr. Yves Cotrel and Professor Jean Dubousset attempted to address all three aspects of planar management (i.e. Coronal, Sagittal and Axial) in the treatment of spinal deformity with the Cotrel-Dubousset (C-D) technique which was later modified by the Texas Scottish Rite Hospital (TSRH) in 1985. Both the C-D and the TSRH techniques required a curved rod and hooks as a spinal fusion construct. Furthermore, the C-D and TSRH technique required that a curved rod be rotated 90 degrees onto its side, utilizing the kyphosis and lordosis of the contoured rod to match the convexity and concavity of the spinal deformity. Once secured, the rod is then rotated to correct the coronal and sagittal balances of the spinal deformity. Subsequently, the C-D or TSRH technique failed to correct the axially unbalanced vertebra. As a result of the unaddressed axial balance, the patient is left with uneven shoulders or hips, also known as “Rotational Trunk Shift.”